How hypoglycaemia unawareness affects us

Hypoglycaemia unawareness, also called impaired awareness of hypoglycaemia, was considered a complication mostly seen in people with type 1 diabetes. But with the increased use of continuous glucose monitors (CGMs), it is now evident that hypoglycaemia unawareness also affects many people with type 2 diabetes who use insulin or other medicines that can influence the onset of hypoglycaemia.

Elizabeth Seaquist, MD, is a professor of medicine at the University of Minnesota, USA. As an expert in hypoglycaemia unawareness, she shares her insights on managing this complication. 

Q: What is hypoglycaemia?

A: Hypoglycaemia occurs when a person’s blood glucose level drops below what is considered a normal value for that person. In healthy people, this fall in glucose is associated with typical symptoms of low blood sugar such as sweating and palpitations. It is relieved by consuming carbohydrates. However, in people with diabetes who are treated with insulin or diabetes medications, the typical symptoms of hypoglycaemia can be reduced when they experience frequent drops in their blood glucose. So, the definitions of hypoglycaemia in people with diabetes are based on the consequences of different levels of hypoglycaemia for each person. 

·       Level 1 hypoglycaemia is when blood glucose is lower than 70 mg/dL. Some people may be used to this level of blood glucose, and they may not have symptoms of hypoglycaemia. However, this value alerts people about the risk for a further fall in glucose, so they can be active by consuming some carbohydrates.

·       Level 2 hypoglycaemia is when blood glucose levels are lower than 54 mg/dL. People may have symptoms that include tremors or sweating when the glycaemia is between 50 mg/dL to 60 mg/dL, but not everybody does. These levels are associated with major consequences, such as losing consciousness. If a person treated with insulin has these readings often, the treatment should be re-evaluated. 

·       Level 3 hypoglycaemia is when a person experiences episodes that require assistance from another person for recovery because they are confused or unconscious. A blood glucose level is not required to define hypoglycaemia in this setting, but with consumption of carbohydrates, or glucagon if they are unable to take something by mouth, the person will be lucid again or recover consciousness.  

Q: What is hypoglycaemia unawareness, and how common is it?

A: Hypoglycaemia unawareness is a condition in which people treated with insulin or diabetes medications have diminished or no ability to perceive the onset of hypoglycaemia level 2. 

If a person never has experienced hypoglycaemia before, their symptoms may begin when their blood glucose level is around 60 mg/dL. However, if someone is exposed to recurrent episodes of hypoglycaemia, the glucose level that triggers symptoms of hypoglycaemia keeps getting lower and lower. So, if yesterday the person had symptoms of hypoglycaemia with a blood sugar of 60 mg/dL, today they might not get symptoms until their glucose level is at 55 mg/dL. While the person’s glucose level threshold for symptoms keeps dropping, unfortunately the glucose level that triggers unconsciousness does not drop. So, the person may not notice their symptoms until it is too late, and they become unconscious.

About 25% of people who have type 1 diabetes experience hypoglycaemia unawareness. You may also see hypoglycaemia unawareness in approximately 10 to 15% of people with type 2 diabetes that use insulin or diabetes medications, and with the use of CGMs, it is becoming evident that this percentage may be higher. The frequency is so high, many people on insulin have hypoglycaemia several times a week.

Q: What are the risk factors for developing hypoglycaemia unawareness?

A: A person must be taking a medicine that influences hypoglycaemia, such as insulin or diabetes medications. We also see other risk factors such as having diabetes for 20 or 30 years, trying too hard to reach low glucose levels, or having trouble managing their diabetes. 

We can also see this in people with impaired cognitive function, dementia, anxiety, or depression, because these problems limit the person’s ability to manage the disease.

Q: What are the complications of hypoglycaemia unawareness?

A: The main complication of hypoglycaemia unawareness is becoming unconscious. Unconsciousness may lead to other problems like car accidents or accidents at work, which may result in severe injury for the person and for others. 

Recurrent episodes of hypoglycaemia may also contribute to long-term problems with brain and heart function. For example, people who have an episode of severe hypoglycaemia are at a greater risk of having a heart attack or a stroke in the next year. 

It is not clear if this is only because of the hypoglycaemia, or if these are just very frail people. Health care professionals should keep this in mind and pay close attention to other risk factors for cardiovascular disease in these patients, such as hypertension and high cholesterol. This also reminds us that these patients should carry instant glucose (glucose chews or glucose liquid shots) with them, and someone—a family member, co-worker, or friend —should know how to access and administer it.

Q: How can health care professionals help patients manage hypoglycaemia unawareness?

A: Continuous glucose monitors are very good tools for patients that are at risk of hypoglycaemia unawareness, because the CGM will alert them if their blood glucose level gets too low. Patients also will know what their blood glucose level is before they drive, and have insights into how food and exercise affect their blood sugars.

Health care professionals should also make sure that patients understand that they need to be aware of some circumstances that may put them at risk. For example, they probably need less insulin overnight on days when they’re very active. The same is true for alcohol—if patients drink alcohol, it increases the risk of hypoglycaemia, so they should be reminded to eat food if they are going to drink. Even the sudden changing seasonality of the weather can be an impactor.

Some studies have shown that if patients avoid hypoglycaemia for some time, they can begin to feel the symptoms of hypoglycaemia again. By preventing hypoglycaemia, you can reset the body to respond differently to symptoms of hypoglycaemia.

It is also important to remember that some patients may be afraid to report episodes of hypoglycaemia to their doctors because of legal implications, eg if driving is a key function of their daily employment. Health care professionals should emphasise to patients that they should know what their blood glucose level is before they drive a car, and that they should have food on hand or instant glucose, so if their glucose level drops, they can manage it.  

Extracts taken from Elizabeth Seaquist, MD, from https://www.niddk.nih.gov